Lateral Flexural-Torsion Buckling of Thin-Walled Cold-Formed Steel Beams with Holes - Design Resistance Evaluation Based on Test Results

Abstract

The paper is focused on problems of the design resistance of thin-walled cold-formed steel beams with holes, respecting the lateral flexural-torsion buckling effects. The attention is mainly paid to the design resistance determination using the results of experimental verification of the objective resistance and their statistic elaboration and probabilistic evaluation. The lateral buckling of thin-walled beams with holes is a specific problem, because of the holes influence on the torsion stiffness, and usual calculating procedures according to the rules given by the European Standards are not always generally usable. The methods based on the approaches of the design assisted by testing are used for the design resistance evaluation, here. The determination of the design resistance using test results respects the statistic characteristics and probabilistic distribution of all input variables, on which the resistance is depended. This method also takes into account the form of the probabilistic model of the resistance, from the viewpoint of the form of mathematical function and its influence on the resistance variability. The design resistance derivation applying the design assisted by testing can be used as an alternative procedure instead of the design resistance determination according to the normative documents, especially in the cases, when the usual procedures are not sufficiently usable.